I dont think there is anything to worry about. My wife lost her EAD(she was not working at the time though and was still maintaining her H4). We did not apply for a replacement as she didn't need it and at the time of renewal, we just attached the top portion of the mailer that came with the first EAD. We didn't even have a copy of the EAD and had no problems in getting the card renewed.
Relax, if you are working using the EAD that you lost you can get a replacement card. You can find the instructions on BCIS website. If you dont need the card right now just take it easy and apply for renewal when it is due using the top portion of the mailer.
cmr